swc-installation-test.py: Add installation-testing script

The content of this script was posted by Greg Wilson and attributed to
Konrad Hinsen [1].

[1]: https://github.com/swcarpentry/website/issues/38#issuecomment-11189525
swc-installation-test.py: Add installation-testing script

The content of this script was posted by Greg Wilson and attributed to
Konrad Hinsen [1].

[1]: https://github.com/swcarpentry/website/issues/38#issuecomment-11189525
workshop_checklist.py: Add installation-testing script

This script was linked to by Eric Bray [1] and hosted on Fernando
Perez's website [2].

[1]: https://github.com/swcarpentry/website/issues/38#issuecomment-11386945
[2]: http://fperez.org/py4science/workshop_checklist.py
workshop_checklist.py: Add installation-testing script

This script was linked to by Eric Bray [1] and hosted on Fernando
Perez's website [2].

[1]: https://github.com/swcarpentry/website/issues/38#issuecomment-11386945
[2]: http://fperez.org/py4science/workshop_checklist.py
Merge Konrad Hinsen and Fernando Perez's installation-testing scripts
Merge Konrad Hinsen and Fernando Perez's installation-testing scripts
swc-installation-test: Consolidate and reorganize test scripts
swc-installation-test: Consolidate and reorganize test scripts
swc-installation-test-2.py: sort CHECKS into topics
swc-installation-test-2.py: sort CHECKS into topics
swc-installation-test-2.py: Add some editors and browsers

Based on a list of possibilities mentioned by Cait Pickens in an
internal email.
swc-installation-test-2.py: Add some editors and browsers

Based on a list of possibilities mentioned by Cait Pickens in an
internal email.
swc-installation-test-2.py: Add virtual-editor and virtual-browser

Often we don't care which editor is installed, so long as at least one
is installed.  This commit tweaks Dependency and adds a
VirtualDependency class to support such virtual dependencies.  You
can't get very fancy with boolean logic, but an all-and and all-or
lists will probably be sufficient for our needs.
swc-installation-test-2.py: Add virtual-editor and virtual-browser

Often we don't care which editor is installed, so long as at least one
is installed.  This commit tweaks Dependency and adds a
VirtualDependency class to support such virtual dependencies.  You
can't get very fancy with boolean logic, but an all-and and all-or
lists will probably be sufficient for our needs.
swc-installation-test-2.py: Add exe_extension for MS Windows compat.

Use distutils' new_compiler() to get the appropriate exe_extension for
the user's system.  This way command names can always be specified in
their bare form, and we'll automatically add the right executable
extension for other platforms.
swc-installation-test-2.py: Add exe_extension for MS Windows compat.

Use distutils' new_compiler() to get the appropriate exe_extension for
the user's system.  This way command names can always be specified in
their bare form, and we'll automatically add the right executable
extension for other platforms.
swc-installation-test-2.py: `PythonDependency`s should depend on Python
swc-installation-test-2.py: `PythonDependency`s should depend on Python
swc-installation-test-2.py: Cache check errors

Avoid running the same check (e.g. 'python') over and over.
swc-installation-test-2.py: Cache check errors

Avoid running the same check (e.g. 'python') over and over.